New research reveals that higher than normal levels of vitamin B12 may indicate that a patient is at risk of developing certain cancers.

Lead researcher Johan Arendt, BSc, of the Department of Clinical Epidemiology and the Department of Clinical Biochemistry of Aarhus University Hospital in Denmark, and colleagues looked at Danish Medical registries. They found the records 333,667 patients without cancer who had been referred for Cbl testing. Researchers did not include patients who had a cancer diagnosis before the date of plasma measurement and those who were receiving Cbl therapy.

The study linked higher Cbl levels to higher risk of cancer overall. Researchers said this is especially true for patients who had higher Cbl levels during the first year after measurement. The findings also revealed that the risk of hematological and alcohol and smoking-related cancers remained high for those with higher Cbl levels after five years of follow up.

Researchers concluded that "...high plasma Cbl levels increased the risk of subsequently diagnosed cancer, mostly within the first year of follow-up."

The noted that high Cbl levels are probably not related to normal Vitamin B12 intake because eating foods or supplements that contain Cbl does not significantly increase plasma Cbl levels. Researchers explain that high Cbl levels may be caused by some unknown malignant process.